The present invention relates to fuse cartridges in general, and more particularly those which are subjected during use to axially directed compressive stresses. For example, cartridges mounted radially on supports which rotate at high speed are subject to sometimes very high centrifugal accelerations.
It is known that in turbo-alternator sets the conventional excitation dynamo has been very often replaced by a small auxiliary polyphase alternator with a rotating armature and a fixed inductor which supplies the rotating inductor of the main alternator by way of semiconductor rectifiers. This dispenses with the commutator of the dynamo hitherto used and also the rings for transmitting its current to the rotor of the alternator. However, semiconductor rectifiers constitute relatively fragile elements which have to be protected, which is achieved by associating with them fuse cartridges, individually mounted on the various phases of the auxiliary alternator. These cartridges are in most cases fixed radially on an annular support integral with the armature of this alternator, so that the centrifugal acceleration to which they are subjected subjects them to axial compressive stresses. Such stresses are not very easily withstood by the conventional cartridges, which tend to become crushed or even to burst.
Experience also shows that the indicating devices associated generally with conventional cartridges, more particularly those of the button or "striker" type, are not very well adapted to resist centrifugal acceleration. Neither are they well suited to the very small voltages which appear at the terminals of a cartridge which has operated, in an auxiliary alternator of the aforesaid type comprising a large number of phases.